Metal-screw machine



(No Model.) 3 Sheets-Sheet l.

A. JOHNSTON.

METAL SCREW MACHINE. No. 269,790. Patented Dec. 26, 1882.

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3 Sheets-Sheet 2.

(No Model.)

A. JOHNSTON. METAL SCREW MACHINE.

No. 269,790. Patented Dec. 26, 1882.

6/.6, YTLa/baaM/ (No Model.) 3 Sheets- Sheet a.

A. JOHNSTON.

METAL SCREW MAOHINE.

No. 269,790. Patented Dec. 26, 1882.

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ALLEN JOHNSTON, or OTTUMWA, IOWA.

METAL-SCREW MACHINE.

SPECIFICATION forming part of Letters Patent No. 269,790, dated December26, 1882.

Application filed February 15, 1882. (No model.

To all whom Lt may concern:

Be it known that I, ALLEN JOHNSTON, of Ottnmwa, in the county of Wapelloand State of Iowa, have invented a new and useful 11nprovement inMetal-Screw Machines, which improvement is fully set forth in thefollowing specification.

The present invention, although applicable in part, at least, to otherforms of screw-machines, is designed more particularly as an improvementon the machines for making metal or machine screws from a long rod orscrewstock which is at intervals and in succession automatically fedforward, turned down, and threaded for a suitable distance, and then hasthe newly-formed screw severed.

The present invention has reference to the general combination andarrangement of the chuck for holding the screw-stock, the milling orturning-down tool, and die orthreadingtool; to the combination of thesame elements with the cutting-off tool; to the form or construction ofthe turning-down, threading, and cutting-01f tools; to a burnisher forremoving the burr left by the cutting-off tool, and to the feeder ormechanism for advancing the. rod or screw-stock.

The accompanying drawings, which form a I part of this specification,represent a screwmachine constructed in accordance with the invention.

Figure l is a central vertical longitudinal section. Figs. 2 and 2.together form a view in horizontalsection and plan. Fig. 3 is a view invertical cross-section on linemrv, Fig. l, and elevation, looking to theright. Fig. 4 is a. similar view in section and elevation, the sectionbeing on line y y, Fig. 1; and Figs. 5, 6, 7, and

S are perspective views of respectively the die i of the threading-tool,the turning-down tool,

the cutting-off tool, and the burnishing-tool or forward.

to shaft B, or by other suitable gearing or mechanical connection. Fromthe gearb motion is conveyed to the die D and its spindle D through thegear cl and shaft (1, gear 0?, and gear (1 the gears d and cl beingkeyed .on the shaft d, and the gear (I on a sleeve, D SllI-' means ofvarying the motion conveyed by gearing can be employed.

The chuck may be of any ordinary or suitable construction. As shown, thechuck-jaws c are fastened at the rear end (left, Fig. 1) to astay-piece, 0, fastened by screws in the end of the chuck spindle, andthe said jaws .are pressed inward to grasp the rod or screw-stock a bythe wedges c on the end of the tube 0 which latter is pressed forward bythe spring The tube 0 with its wedges, is at intervals drawn backagainst the pressure of the spring 0 to relieve the bite of the jaws con the screw-stock a and allow the latter to be fed The means forreleasing the jaws comprise a bent lever, a, pivoted on a crossshal't, aand operated by a projection, a on the can'i-disk E, itself keyed to theshaft B. On the opposite end of the shaft B is a cam- (lrum, E, by whichthe tools aremade to 0pcrate on the screw-stock through suitableconnections The threading-tool, as well as the other tools,

to be hereinafter described, is brought into action while thescrew-stock is held in the chuck. Being revolved faster than said chuck,it cuts the thread or the screw-stock in proportion to the difference inthe velocities of rotation. In order to run the die off the newly-cutthread, the die and its spindle D are held from turning by a projection,e, on the non-rotating clutch-bare, which is supported in guides, and iscapable ofaslighttbrward movement against the pressure of the spring 6So far, broadly considered, there is nothing new in the machine.teference may be had to Letters Patent No. 24L,8U6, granted to me ;\[ay24, 1881, and to my application for pat ent, No. 35,250, dated July 21,1881. The ma chinery explained is shown herein as being best suited foruse in connection with the improvements constitutingthe presentinvention. These improvements are not, however, limited to suchmachinery.

The improvement in turning down and threading the screw-stock will nowbe described.

instead of bringing the turning-down tool in line with the screw-stock,advancing it to mill said stock,returning or backingit otf, and movingit out of the way, and then bringing the threading tool or die intoposition, the turning-down and threading tools are advanced together,and together act upon the screwstock, the tnrningdown tool somewhat inadvance of the threading-tool.

F is the milling or turning-down tool, carried by a slide, F, supportedin ways of the slide G, which carries the die or threadingtool, and isitself supported in guides of the machine-frame. The slide G is movedlongitudinally back and forth by means of the irregular cam fon the drumE acting upon the pin f, projecting downward from the slide Gr. Onebearing of shaft dis carried by slide G, and is capableot' sliding onthe shaft. The gear (I is made long to allow the desired motion to thesleeve on which it is fixed without disengaging its teeth from those ofgear d".

The ways of slide F are transverse to and preferably slightly oblique tothe axis of the chuck and die-spindle.

The object of carrying the turning-down tool on a slide is mainly toenable it to be moved out of the way of the die or threadingtool aftermilling the desired length of screwstock. This removal is necessary inmaking screws with shanks threaded to the head; but when snllicientlength of the shank is left unthreaded it isnot necessary, and then theslide permits an adjustment of the turning-down tool so as to leave alarger or smaller shank to the screw.

For removing the turning-down tool from the path of the threading-tool,a spring, g, latch g, and locking-bar {12MB combined with the slide F,and a fixed pr jection, g, on the machineframe. The springg is fastenedat one end to the slide G, and at its free end engages II] a notch, g,in the slide F. The latchyis pivoted to the slide G, and carries aspring, 1 which presses at its free end against a pin,g on the slide G.The locking-barg is fastened to the slide F by the screws 9 9 the screwypassing through a slot, which allows to the bar 9" an adjustment on thescrew gas a center. During the action oftheturning-down tool the slideFis held in placeagainsttt he pressure of the spring g by the engagementof the locking-bar g with the latch g. When the desired length of screwhas been turned down or milled the latch 9 strikes the fixed projection9 is retracted against the pressure of its spring g, releasing thelocking-barg and allowing the springgto shift the slide F and move theturningtool F away from the screw-stock a The slide G continues toadvance until the thread has been cut, when it is returned by the actionof the cam f. During the return movement the slide F is moved toward theaxis of the chuck by the contact of its inclined end with the fixedprojection 9 the latch y snaps into engagement with the locking-bar g,and the turningdown tool F is again in position for advancing to turndown or mill the stock a for another screw. By adjusting the position ofthe latch g the position of the turning-down tool will be regulated tomill screw-shanks of different diatneters.

The ways of the slide F could be made at right angles to the axis of thechuck and die; but the oblique position shown is preferred, because itgives to the turningdown tool in withdrawing frotu the screw-stock aslight backward movement that offsets the forward movement of the slideGr, so that the under side of the screw-head is left perfectly square.

The turning-down tool and threading-tool may be so arranged that thelatter will not begin to cut the thread until the milling operation iscompleted; but they are so arranged that the threading-tool begins toact alter the other tool has turned down the screw-stock for a shortdistance,and the two then continue to act together, and besides thesaving of time and movement there is a special advantagein this when, asin the machine shown, the thread is cut by running the die faster thanthe chuck and screw-stock, which advantage is that the pressures of thedie and turning-down tool, being in opposite directions, partlycounterbalance each other and the strain on the chuckjaws is relieved.

\Vhen the screw-shankis not to bethreaded all the way up to the head theslide F is held in place by the set-screw h,and the threading, whichbegins shortly after the turning down has commenced, stops at the sametime with it.

In order to prevent the rod or screw-stock a from springing away fromthe turning-down tool, asupporting arm or rest, H,is used. This arm orrest is supported on the slide Gr independently of the turning-down ormilling tool, and it bears against the screw-stock (t on the sideopposite from the said turning-down 0r milling tool. As shown, it bearsagainst the full pfirtion ot the screw-stock; but it could be made alsoor instead to bear against the turned-down portion.

The cutting-off tool I is carried by a slide, K, supported in ways ofthe machine-frame transverse to the movement of the slide G. It isoperated by a bent lever, K, pivoted at k to the machine-fratne, andhaving its ends loosely connected respectively with the slide K and theslide Gr. During the retreat of the latter with the threading andturning-down tools,

,let't by the cutting-off tool.

the slide K and the cutting-oft tool I are advanced, and thenewly-formed screw is severed from the screw-stock by the cutting-ofttool. .When the slide G is again advanced the slide K is withdrawn. Thelever K could be oper ated by a separate cam on the drum E, as in myapplication before mentioned; but theconstruction shown is simpler andbetter, and is therefore claimed as an improvement.

. In connection with the cutting-01f tool, a burnisher, L, is employedto remove the burr It is so placed that when advanced the cuttiugedge lpasses just over the screw-stock, removing any burr that may be thrownup by-the cutting-offtool. The burnisher also serves as a rest orsupport to hold the rod or screw-stock up, or, rather, down, to thecutting-0d tool. As shown, it is carried by the slide K, being attachedto the same support as the cutting-oft tool.

The several tools have heretofore been referred to generally, sincetools of any ordinary or suitable construction may be used. The specialform or construction of the tools, as shown, however, constitutes a partof the invention, and will next be described.

The turning-down tool F consists of a disk (see Fig.6) with a portionremoved, and ground to leave a cutting-edge, m, to act upon thescrew-stock. The said disk is also provided with a boss, at, which has acutting-edge t'or shaving down the head of the screw, being made to forma smooth screw-head. The tool is supported by a bolt, m that passesthrough a central aperture in the disk and binds the latter against theupright m on the slide F. This style of tool lasts a long time, as thecutting-edge can be sharpened from time to time, and the tool used untilalmost the entire periphery is worn away. Moreover, after each grindingthe cutting edge is always the same, so that the work done will beuniform. The new cutting-edge can be brought to the proper positionrelative to the stock by turning the disk-tool on the bolt m andsecuring it in such position.

The die D is formed of a split tube or pipe cut away on the side, asshown at n, Fig. 5, and underneath, as at a, to form the three jaws orspringarms n having their cuttingedge on the inside. The outside of thearms is made tapering, and is threaded to receive a solid ring or nut, nBy turning this nut toward the solid end of the die theeuds ot' thespring-arms will be drawn together, owingto the taper form of theexterior, and by turning the nut in the opposite direction the ends ofthe spring-arms are allowed to separate, so that it is very easy toadjust the threading-die to the exact size wanted. When thejaws orspringarms n are drawn together each jaw so moves that certain partstend directly toward the axis of the die, so that; it their motion werecontinued they would pass through said axis, other parts passing to theside ot'the axis. The parts of each jaw which tend directly toward theaxis lie in the radial plane which, roughly speaking, bisects the baseof thejaw. By shaping the notches n as shown this plane intersects theforward corner, a, of the cutting-edge, or is brought close to saidcorner, sothat whatever the. adjustment of the cutting-edges toward andaway from the axis of thedie these corners will always be nearest theaxis and act first upouthescrew-shank. It is therefore practicable togrind the cutting-edges and set them until the die'is worn out.

The die I) is screwed on the end of the diespindle. A head, N, is heldon the spindle,

between the die D and a shoulder, 19, on the die-spindle, and it is ormay be keyed to said spindle; The head N is cut away on the periphery,as shown at P, Fig. 2, to leave an annular space for the reception ofthe projection e on the clutch-bar 0 during the threading operation, anda stop, 12 to engage the said projection and hold the die and spindlestationary t'or uuthreading the die. One partot' the clutch D is alsoformed on this head. The cuttingoff tool I, like the turning-down ormilling tool, is discoidal and possesses the advantages beforeenumerated for that form of tool.

The burnisher L is made in the same form, only the curved edgeconstitutes a smaller part of a circle. As shown, both it and thecuttingoff tool are supported on one bolt, g, which passes through theircenters, and by which they are fastened to the upright q on the slide K,and the burnisher is bent so that its periphery lies on the same planewith that of the cutting-off tool, the outer bent portion fitting in therecess 2' of the cuttii'ig-ofi' tool.

The mechanism for feeding the rod or screwstock it at intervals, whenthe bite of the chuckjaws is released, will next be described.

A bar, Q, is screwed into the machine-frame, or otherwise supported.This bar is somewhat longer than the rods or stocks from which thescrews are to be made. It is recessed on top to receive a rack-bar, Qf,which is reciprocated in its recess by the lever Q acting to move itforward, (to the right, Fig. 1,) and the spring Qtaeting to return it.The lever Q? is oper ated by the cam Q on the disk E.

Mounted on the bar Q is a sliding carriage, R, provided with a pawl, 9',that takes into the teeth of the rack-bar Q. A feed-bar, R, has itsouter end supported and journaled in a bearing on the carriage R, and atits inner end it is connected with the outer end of a rod or screwstock. The shoulder r and nut r on the feed-bar cau e it to move backand forth with the carriage It. A supportingguide, S, steadies thefeed-bar.

The connection with the end of the rod or screw-stock is made by recessiug the end, as ats, splitting it, and holding the two parts together bya clamp or set-screw, s.

The feed-bar is cylindrical and smaller in diameter than the bore of thetube 0", and in operation it enters said tube, pushing the rod orscrew-stock d in front of it. The intermit- IlO IIS

tent forward movement of the carriage R and feed-bar It is communicatedto them by the cam Qthrough the cam-lever Q rack-bar Q, and pawl 7'. Theforward movement takes place while the chuck-jaws are released from thescrew-stock, and when said movement is completed thejaws again take holdof the rod or screw-stock, the cam Q passes away from the end of lever Qallowing the spring Q to assert itself and return the rack-bar withoutthe carriage It, the pawl r dropping into engagement with a new tooth.

The forward movement of the rack-bar can be regulated by means of theadjusting-screw tat the lower end of the lever Q which makes contactwith cam Q. The distance between the teeth of the rack-bar willordinarily be equal to a .-crews length, and by substituting rack-barswit ii different sizes of teeth the rod or screw-stock may be advancedthe distance required by different lengths of screws. When a rod orscrew-stock has been used up the carriage and feed-bar can be run backby hand. This feed mechanism is more positive in its action than thesplit tube commonly employed.

it may be observed, however, that heretofore msitively-operating mchanism has been used for feeding. For example,aearriage in which therod or screw-stock is supported so as to be capable of revolution hasbeen advanced step by step through the reciprocation of a rack-bar, anda feed-bar adapted to enter the hollow chuck-s 'iindle has been advancedby a rack and pawl. These old apparatus are of course not included inthe present invention.

Having explained the construction and operation ot the several parts ofthe machine, a brief description of the operation of the entire machinewill be given.

Motion being imparted to the chuck and its spindle O by a belt orpulley, O, and conveyed thence to the cam-shaft, B, and die I), and itsspindle D, the die and its spindle revolving faster than the chuck, thetools commence to operateontherodorscrew-stock a,which,previous to thestartingof the machine, has had its front end inserted through the tube0 and between the chuck-jaws c, and the rear end clamped in the recessedend of the feed-bar 1%. After the lever a. has been released by the cam09, and the chuck-jaws 0 have taken hold of the rod oi-serew-stock a,the slide G is advanced slowly, bringing the turning-down tool F firstinto action,and then the threading-tool, the rod or screw-stock beingheld up to the turning-down tool by the arm or rest H. \Vhen the properlength of rod has been turned down by the tool F the latch g strikes thelixed projection g and releases the locking-bar g and the tool Fisremoved by the spring 9. The threadingtool continues to cut until themovementof the slide G is reversed by the cam f. This cam, when theforward movement of the slide is finished, draws hack the slide,suddenly disengaging the clutch l) and engaging the stoppiece orclutch-bar a with the projection 12 on threaded screws.

the head N. The slide then continues to back off more slowly until thedie 1) is released from the thread, and the cutting-elf tool I andburnisher L have acted upon the rod, the former to sever thenewly-formed screw and the latter to remove the burrthrown up by theformer. The slide G, with the turning-down and threading tools, thenbegins its forward motion, when the chuck-jaws 0 are released by the camat, and at the same time the rod or screw-stock is advanced through themby the action-of the cam Q lever Q rack-bar Q, and pawl r. Thechuck-jaws then resume their hold on the rod or screw-stock, therack-bar is returned into position for a new feed, and the operationsproceed as before. If the screws are to be threaded only part way to thehead, the slide F will be held in position by the setscrew h.

It isobvious that modilicationsmay be made in the details ofconstruction without departing from the spirit of the invention, andthat portions of the invention may be used without. the others. Forexample, a die and turningdown tool, operating as described, could becombined with a chuck the rotation of which is reversed to unthread thedie, or could be used in a machine in which the die is unthreaded bybeing run faster than the chuck, or in other machines.

The several parts of the invention, so far as applicable, can be usedfor making nuts or op crating upon .other articlcs,as well as for makingscrews. The machine may also be modified by supporting the tools on. themachineframe, and impartinglongitudinal and lateral movement to thechuck instead of to the turning-down or milling tool and thethreading-tool, as in the machine described in my application No.44,658, filed October 28, 1881, only in such case it is obvious thelateral movement of the chuck will only be employed to sever the Theinvention is in part applicable to what are known as hand machines, incontradistinctiou to automatic machines.

Having now fully described my said invention and the manner of carryingthe same into etfect, what I claim isl. The combination, with thc chuckadapted to receive a long rod orscrew-stock, the means for relieving andrestoring the pressure of the chuck-jaws and for advancing therod orscrewstoek when the pressure of the chuck-jaws is relieved, thecutting-off tool, and the longitudinal slide, of the threading andturningdown tools supported on said slideand adapted for simultaneousaction, the said turning-down tool being supported within less than thedistance of a screws length immediately in advance of thethreading-tool, substantially as described.

2. The combination, with the chuck, of the screw'cutting die, and theturning-down tool supported within less than a screws length in front ofsaid die, and adjusted to turn down the screw-stock to the interiordiameter of said die, so that the turning down and threading proceedsimultaneously, substantially as described.

3. The combination of the chuck, the longitudinal slide, theturning-down tool, the latexally-movable support for said tool, andautomatic mechanism-such as the spring, latch, and releasing projectionshown and described-t'or withdrawing the aforesaid sup-. portduringtheforward movement of said slide, substantially as set forth.

4. The combination of the chuck,theturningdown tool, an additionalcutting-tool-sucb as the threading-toolsupported behind saidturning-down tool, the longitudinal slide, thelaterally-movablesupportfortheturning-down tool, and the automaticmechanism for withdrawing the aforesaid support during the forwardmovement of said slide, said tools, to-

gether with the laterally-moving support for the turning-down tool,being carried by the longitudinal slide, substantially as described.

The combination of the chuck, the longitudinal slide, the turning-downtool, an additional cutting-tooL-such as the threading tool-supportedbehind said turning-down tool-the laterallymovable support for theturning-down tool, and the automatic mechanism for withdrawing andreturning the said support, said tools, with the laterally-movingsupport for the turning-down tool, being carried by the longitudinalslide, substantially as described.

(5. The combination, with the chuck, the threading-tool, and themechanism for revolving the same, ot'the longitudinal slide, and thetnrningdown tool supported immediately in front of said threading-tool,the parts being constructed and arranged, substantially as described, sothat the said tools act upon the screw-stock in opposite directions andin part, at least, simultaneously.

7. The combination of the chuck, the longitudinal slide, thethreading-tool, the turningdown tool supported on said slide in front ofsaid threading-tool, and the cam and-connections or equivalent automaticmechanism for reciprocating said slide, substantially as described.

8. The combination of the chuck, the longitudinal slide, thethreading-tool, the turningdown tool supported on said slide in front ofsaid threading-tool, the laterally-movable support for the turning-downtool, the cam and connections or equivalent automatic mechanism t'orreciprocating said slide, and the automatic mechanism for withdrawingand returning the aforcsaidsupport, substantial y as de scribed.

9. The combination, with the chuck adapted to receive a long rod orscrew-stock and mechanism for feeding the said rod or stock a screwslength ata time, ofthelongitudinal slide, a cntting-tool-such as thethrcading-toolsupported on said slide, a second cutting-toolsuch as theturning-down tool-supportedalso on said slidein frontof the first-namedtool, the cutting-oh tool, and the automatic mechanism for operatingsaid cutting-oft tool, substantially as described.

10. The combination of the chuck adapted to receive a long rod orscrew-stock, mechanism for feedingthesaid rod orstock through the chuck,the longitudinal slide, a cutting-toolsuch as thethreading-tool-snpported on said slide, a second cutting-tool-such asthe turning-down tool-supported also on said slide in frontof thefirst-named tool on a laterallymovable support, the automatic mechanismfor withdrawing-and returning the said support, the cutting-off tool,and the automatic mechanism for operating the same, substantially asdescribed.

1]. The combination of the chuck adapted to receive a long rod orscrew-stock,automatic mechanism for feeding the said rod or screwstock,the longitudinal slide,the cam and connections or equivalent automaticmechanism for reciprocating the said slide, two cuttingtoolssuch as thethreading-tool and theturning-downtool-supported on the aforesaid slidethe one behind the other, the cutting-0ft tool, and automatic mechanismfor operating said cutting-oft tool, substantially as described.

12. The combination of the chuck adapted to receive arod orlongscrew-stock, automatic feeder for said rod or screw-stock, thelongitudinal slide, the cam and connections or equivalent automaticmechanism for reciprocating .said slide, the threading-tool supported onsaid slide, the turning-down tool supported also on said slide in frontof said threadingto'ol, the laterally-movable support for theturning-down tool, the automatic mechanism for withdrawing and returningthe same, the cutting-off tool,and the automatic mechanism for operatingsaid cutting-off tool, substantially as described.

13. The combination, with the chuck, the longitudinal slide, and one ormore cuttingtools-such as turning-down and threading tools-ot'thecutting-offtool and the device connecting its support with said slide sothat the cutting-off tool is operated by the reciproca tion of saidslide, substantially as described.

14. In an automatic machine for forming screws from a long rod orscrew-stock, the combination, with the chuck, of the automaticmechanism,substantially as described,torturning down and simultaneouslythreading the end of the rod or screw-stock and for severing thenewly-formed screw.

15. Thecombination,withthethreading-tool and the turning-down toolsupported in front of said threading-tool, of the rest attached at therear to theframe supporting the threading tool and projecting forward toa point opposite the turning-down tool, substantially as de scribed.

16. The combination, with the chuck, the longitudinal slide, and the camand connections or equivalent automatic mechanism for reciprocating saidslide, of the threading-tool, the turning-down tool, and the rest forholding the work to the turning-down tool, said tools and rest beingcarried by said slide, substantially as described.

17. The combination, with the chuck and cutting-otftool, of theburnisher for removing the burr thrown up by the said tool before thelatter has completely severed the article, substantially as described.

18. ThecombinationOfthechuck,thethreading-tcol, the cutting-otftool, theburnisher, and mechanism foroperatingsaid devices, substantially asdescribed.

19. The combination of a cutting-toolsuch as the cutting-01f tool-theburnisher. for removing the burr thrown up by aforesaid tool, the commonsupporting-slide, and mechanism for reciprocating said slide,substantially as described.

20. The combination, with the chuck and the turning-down and threadingtools of a screw-machine, of the automatic mechanism, substantially asdescribed, for advancing the turning-down and threading tools, formoving the turningdown tool aside, for backing 011" the said tools, andfor returning the turningdown tool into position for again acting uponthe screw-stock, as set forth.

2]. The combination, with the revolving chuck, the turning-down tool andthreadingtool, and mechanism for bringing said tools successively intoaction-the threading-tool after the turning-down tool, and whilethelatter is acting upon the screw-stockof mechanism for revolving thethreading-tool in the same direction as the chuck, but at a differentspeed, so that the velocity of rotation of said screwstock is greaterwith reference to said turningdown tool than to said threading-tool,substantially as described.

22. The combination ofthe discoidal cuttingoff tool and the burnishersupported on a common center, substantially as described.

23. Thediscoidal turning-down tool provided with the boss adapted toshave the head at the same time that the turning-down operation isperformed, substantially as described.

24. The split die having a tapering or coni cal exterior, screw-threadedas described, in combination with the nut or solid ring engaging saidthread and adapted to adjust the position of the cutting-edges,substantially as described.

25. The split die having spring-jaws separated by wedge-shaped notches,whereof one side is parallel, or nearly so, with the longitudinal axisof the die, and the other side is inclined thereto, substantially asdescribed.

26. The combination, with the chuck and mechanism for relieving andrestoring the bite of the chuck-jaws, ot' the fced-barjournaled in thesliding carriage, and provided at its forward end with means forclamping the rod or screw-stock, and of mechanism for advancing saidfeed-bar and carriage step by step, sub stantially as described.

27. In a machine having a chuck and hollow chuck-spindle, thecombination, with the sliding carriage, the pawl, the rack-bar, andmechanism for reciprocating the rack-bar, of the feed-bar adapted toenter the said spindle and journaled in the said carriage, substantiallyas described.

28. The combination, with the chuck, the mechanism for releving andrestoring the bite of the chuck-jaws, the tools for acting on the rod orscrew-stock, and the operating mechanism, ot' the feeder comprising thesliding carriage, the pawl, the rack-bar, the feed-bar, and the cam forrociprocating the rack-bar, substantially as described.

29. The combination, with the longitudinal slide on which thethreading-tool is mounted, and the transverse slide carrying theturningdown tool,of the spring attached at one end to the longitudinalslide and at the other engaging the transverse slide, thelatch, thelockingbar, and the fixed projection on the machine-frame, substantiallyas described.

30. The combination, with the chuck, the longitudinal slide, and thethreading-tool carried thereby, of the transverse slide for theturning-down tool, arranged slightly oblique to the axis of thethreading-tool, substantially as described.

In testimony whereofl have signed this specification in the presence oftwo subscribing witncsscs.

ALLEN JOHNSTON.

SVitnesses:

J. T. HAOKWORTH, \V. T. MAJOR.

